Reland "Turn the DOWN_CAST_COMPOSITE strong mode error into a hint, which will"

pkg/analyzer/test/src/task/strong/checker_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.test.src.task.strong.checker_test;
 
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'strong_test_helper.dart';
 
@@ skipping 1061 matching lines @@
   Bottom bot;
   {
     Top f;
     f = top;
     f = left;
     f = right;
     f = bot;
   }
   {
     Left f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
     f = left;
     f = /*error:INVALID_ASSIGNMENT*/right;
     f = bot;
   }
   {
     Right f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
     f = /*error:INVALID_ASSIGNMENT*/left;
     f = right;
     f = bot;
   }
   {
     Bottom f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
-    f = /*warning:DOWN_CAST_COMPOSITE*/left;
-    f = /*warning:DOWN_CAST_COMPOSITE*/right;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/left;
+    f = /*info:DOWN_CAST_COMPOSITE*/right;
     f = bot;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_dynamic_knownFunctions() async {
     // Our lattice should look like this:
     //
     //
@@ skipping 53 matching lines @@
         botTop
                       );
   }
   {
     ATop f;
     f = topA;
     f = topTop;
     f = aa;
     f = aTop;
     f = /*error:INVALID_ASSIGNMENT*/botA;
-    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
+    f = /*info:DOWN_CAST_COMPOSITE*/botTop;
     apply/*<ATop>*/(
         topA,
         topTop,
         aa,
         aTop,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
     apply/*<ATop>*/(
         (dynamic x) => new A(),
         (dynamic x) => (x as Object),
         (A x) => x,
         (A x) => null,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
   }
   {
     BotA f;
     f = topA;
     f = /*error:INVALID_ASSIGNMENT*/topTop;
     f = aa;
     f = /*error:INVALID_ASSIGNMENT*/aTop;
     f = botA;
-    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
+    f = /*info:DOWN_CAST_COMPOSITE*/botTop;
     apply/*<BotA>*/(
         topA,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/topTop,
         aa,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/aTop,
         botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
     apply/*<BotA>*/(
         (dynamic x) => new A(),
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(dynamic x) => (x as Object),
         (A x) => x,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object),
         botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
   }
   {
     AA f;
     f = topA;
     f = /*error:INVALID_ASSIGNMENT*/topTop;
     f = aa;
     f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
-    f = /*warning:DOWN_CAST_COMPOSITE*/botA;
-    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
+    f = /*info:DOWN_CAST_COMPOSITE*/botA;
+    f = /*info:DOWN_CAST_COMPOSITE*/botTop;
     apply/*<AA>*/(
         topA,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/topTop,
         aa,
         /*error:INVALID_CAST_FUNCTION*/aTop, // known function
-        /*warning:DOWN_CAST_COMPOSITE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botA,
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                   );
     apply/*<AA>*/(
         (dynamic x) => new A(),
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(dynamic x) => (x as Object),
         (A x) => x,
         /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
-        /*warning:DOWN_CAST_COMPOSITE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botA,
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                   );
   }
   {
     TopTop f;
     f = topA;
     f = topTop;
     f = /*error:INVALID_ASSIGNMENT*/aa;
     f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
     f = /*error:INVALID_ASSIGNMENT*/botA;
-    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
+    f = /*info:DOWN_CAST_COMPOSITE*/botTop;
     apply/*<TopTop>*/(
         topA,
         topTop,
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/aa,
         /*error:INVALID_CAST_FUNCTION*/aTop, // known function
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                       );
     apply/*<TopTop>*/(
         (dynamic x) => new A(),
         (dynamic x) => (x as Object),
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(A x) => x,
         /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
         /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                       );
   }
   {
     TopA f;
     f = topA;
     f = /*error:INVALID_CAST_FUNCTION*/topTop; // known function
     f = /*error:INVALID_CAST_FUNCTION*/aa; // known function
     f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
-    f = /*warning:DOWN_CAST_COMPOSITE*/botA;
-    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
+    f = /*info:DOWN_CAST_COMPOSITE*/botA;
+    f = /*info:DOWN_CAST_COMPOSITE*/botTop;
     apply/*<TopA>*/(
         topA,
         /*error:INVALID_CAST_FUNCTION*/topTop, // known function
         /*error:INVALID_CAST_FUNCTION*/aa, // known function
         /*error:INVALID_CAST_FUNCTION*/aTop, // known function
-        /*warning:DOWN_CAST_COMPOSITE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botA,
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
     apply/*<TopA>*/(
         (dynamic x) => new A(),
         /*error:INVALID_CAST_FUNCTION_EXPR*/(dynamic x) => (x as Object), // known function
         /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => x, // known function
         /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
-        /*warning:DOWN_CAST_COMPOSITE*/botA,
-        /*warning:DOWN_CAST_COMPOSITE*/botTop
+        /*info:DOWN_CAST_COMPOSITE*/botA,
+        /*info:DOWN_CAST_COMPOSITE*/botTop
                     );
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_dynamicFunctions_closuresAreNotFuzzy() async {
     // Regression test for definite function cases
     // https://github.com/dart-lang/sdk/issues/26118
     // https://github.com/dart-lang/sdk/issues/26156
@@ skipping 118 matching lines @@
     Function2<B, A> top;
     Function2<B, B> left;
     Function2<A, A> right;
     Function2<A, B> bot;
 
     top = right;
     top = bot;
     top = top;
     top = left;
 
-    left = /*warning:DOWN_CAST_COMPOSITE*/top;
+    left = /*info:DOWN_CAST_COMPOSITE*/top;
     left = left;
     left = /*error:INVALID_ASSIGNMENT*/right;
     left = bot;
 
-    right = /*warning:DOWN_CAST_COMPOSITE*/top;
+    right = /*info:DOWN_CAST_COMPOSITE*/top;
     right = /*error:INVALID_ASSIGNMENT*/left;
     right = right;
     right = bot;
 
-    bot = /*warning:DOWN_CAST_COMPOSITE*/top;
-    bot = /*warning:DOWN_CAST_COMPOSITE*/left;
-    bot = /*warning:DOWN_CAST_COMPOSITE*/right;
+    bot = /*info:DOWN_CAST_COMPOSITE*/top;
+    bot = /*info:DOWN_CAST_COMPOSITE*/left;
+    bot = /*info:DOWN_CAST_COMPOSITE*/right;
     bot = bot;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_higherOrderFunctionLiteral1() async {
     await checkFile('''
 class A {}
 class B extends A {}
 
 typedef T Function2<S, T>(S z);
 
 typedef A BToA(B x);  // Top of the base lattice
 typedef B AToB(A x);  // Bot of the base lattice
 
 BToA top(AToB f) => f;
 AToB left(AToB f) => f;
 BToA right(BToA f) => f;
-AToB bot_(BToA f) => /*warning:DOWN_CAST_COMPOSITE*/f;
+AToB bot_(BToA f) => /*info:DOWN_CAST_COMPOSITE*/f;
 AToB bot(BToA f) => f as AToB;
 
 void main() {
   {
     Function2<AToB, BToA> f; // Top
     f = top;
     f = left;
     f = right;
     f = bot;
   }
@@ skipping 28 matching lines @@
 class B extends A {}
 
 typedef T Function2<S, T>(S z);
 
 typedef A BToA(B x);  // Top of the base lattice
 typedef B AToB(A x);  // Bot of the base lattice
 
 Function2<B, A> top(AToB f) => f;
 Function2<A, B> left(AToB f) => f;
 Function2<B, A> right(BToA f) => f;
-Function2<A, B> bot_(BToA f) => /*warning:DOWN_CAST_COMPOSITE*/f;
+Function2<A, B> bot_(BToA f) => /*info:DOWN_CAST_COMPOSITE*/f;
 Function2<A, B> bot(BToA f) => f as Function2<A, B>;
 
 void main() {
   {
     Function2<AToB, BToA> f; // Top
     f = top;
     f = left;
     f = right;
     f = bot;
   }
@@ skipping 28 matching lines @@
 class B extends A {}
 
 typedef T Function2<S, T>(S z);
 
 typedef A BToA(B x);  // Top of the base lattice
 typedef B AToB(A x);  // Bot of the base lattice
 
 BToA top(Function2<A, B> f) => f;
 AToB left(Function2<A, B> f) => f;
 BToA right(Function2<B, A> f) => f;
-AToB bot_(Function2<B, A> f) => /*warning:DOWN_CAST_COMPOSITE*/f;
+AToB bot_(Function2<B, A> f) => /*info:DOWN_CAST_COMPOSITE*/f;
 AToB bot(Function2<B, A> f) => f as AToB;
 
 void main() {
   {
     Function2<AToB, BToA> f; // Top
     f = top;
     f = left;
     f = right;
     f = bot;
   }
@@ skipping 34 matching lines @@
     Function2<Function2<A, B>, Function2<B, A>> top;
     Function2<Function2<B, A>, Function2<B, A>> right;
     Function2<Function2<A, B>, Function2<A, B>> left;
     Function2<Function2<B, A>, Function2<A, B>> bot;
 
     top = right;
     top = bot;
     top = top;
     top = left;
 
-    left = /*warning:DOWN_CAST_COMPOSITE*/top;
+    left = /*info:DOWN_CAST_COMPOSITE*/top;
     left = left;
     left =
         /*error:INVALID_ASSIGNMENT*/right;
     left = bot;
 
-    right = /*warning:DOWN_CAST_COMPOSITE*/top;
+    right = /*info:DOWN_CAST_COMPOSITE*/top;
     right =
         /*error:INVALID_ASSIGNMENT*/left;
     right = right;
     right = bot;
 
-    bot = /*warning:DOWN_CAST_COMPOSITE*/top;
-    bot = /*warning:DOWN_CAST_COMPOSITE*/left;
-    bot = /*warning:DOWN_CAST_COMPOSITE*/right;
+    bot = /*info:DOWN_CAST_COMPOSITE*/top;
+    bot = /*info:DOWN_CAST_COMPOSITE*/left;
+    bot = /*info:DOWN_CAST_COMPOSITE*/right;
     bot = bot;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_instanceMethodVariance() async {
     await checkFile('''
 class A {}
 class B extends A {}
@@ skipping 11 matching lines @@
   C c = new C();
   {
     Function2<B, A> f;
     f = c.top;
     f = c.left;
     f = c.right;
     f = c.bot;
   }
   {
     Function2<B, B> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
+    f = /*info:DOWN_CAST_COMPOSITE*/c.top;
     f = c.left;
     f = /*error:INVALID_ASSIGNMENT*/c.right;
     f = c.bot;
   }
   {
     Function2<A, A> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
+    f = /*info:DOWN_CAST_COMPOSITE*/c.top;
     f = /*error:INVALID_ASSIGNMENT*/c.left;
     f = c.right;
     f = c.bot;
   }
   {
     Function2<A, B> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.left;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.right;
+    f = /*info:DOWN_CAST_COMPOSITE*/c.top;
+    f = /*info:DOWN_CAST_COMPOSITE*/c.left;
+    f = /*info:DOWN_CAST_COMPOSITE*/c.right;
     f = c.bot;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_intAndObject() async {
     await checkFile('''
 typedef Object Top(int x);      // Top of the lattice
 typedef int Left(int x);        // Left branch
@@ skipping 21 matching lines @@
   }
   {
     Top f;
     f = top;
     f = left;
     f = right;
     f = bot;
   }
   {
     Left f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
     f = left;
     f = /*error:INVALID_ASSIGNMENT*/right;
     f = bot;
   }
   {
     Right f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
     f = /*error:INVALID_ASSIGNMENT*/left;
     f = right;
     f = bot;
   }
   {
     Bot f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/top;
-    f = /*warning:DOWN_CAST_COMPOSITE*/left;
-    f = /*warning:DOWN_CAST_COMPOSITE*/right;
+    f = /*info:DOWN_CAST_COMPOSITE*/top;
+    f = /*info:DOWN_CAST_COMPOSITE*/left;
+    f = /*info:DOWN_CAST_COMPOSITE*/right;
     f = bot;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_namedAndOptionalParameters() async {
     await checkFile('''
 class A {}
 
@@ skipping 21 matching lines @@
    r = r;
    r = o;
    r = /*error:INVALID_ASSIGNMENT*/n;
    r = /*error:INVALID_ASSIGNMENT*/rr;
    r = ro;
    r = rn;
    r = oo;
    r = /*error:INVALID_ASSIGNMENT*/nn;
    r = /*error:INVALID_ASSIGNMENT*/nnn;
 
-   o = /*warning:DOWN_CAST_COMPOSITE*/r;
+   o = /*info:DOWN_CAST_COMPOSITE*/r;
    o = o;
    o = /*error:INVALID_ASSIGNMENT*/n;
    o = /*error:INVALID_ASSIGNMENT*/rr;
    o = /*error:INVALID_ASSIGNMENT*/ro;
    o = /*error:INVALID_ASSIGNMENT*/rn;
    o = oo;
    o = /*error:INVALID_ASSIGNMENT*/nn;
    o = /*error:INVALID_ASSIGNMENT*/nnn;
 
    n = /*error:INVALID_ASSIGNMENT*/r;
    n = /*error:INVALID_ASSIGNMENT*/o;
    n = n;
    n = /*error:INVALID_ASSIGNMENT*/rr;
    n = /*error:INVALID_ASSIGNMENT*/ro;
    n = /*error:INVALID_ASSIGNMENT*/rn;
    n = /*error:INVALID_ASSIGNMENT*/oo;
    n = nn;
    n = nnn;
 
    rr = /*error:INVALID_ASSIGNMENT*/r;
    rr = /*error:INVALID_ASSIGNMENT*/o;
    rr = /*error:INVALID_ASSIGNMENT*/n;
    rr = rr;
    rr = ro;
    rr = /*error:INVALID_ASSIGNMENT*/rn;
    rr = oo;
    rr = /*error:INVALID_ASSIGNMENT*/nn;
    rr = /*error:INVALID_ASSIGNMENT*/nnn;
 
-   ro = /*warning:DOWN_CAST_COMPOSITE*/r;
+   ro = /*info:DOWN_CAST_COMPOSITE*/r;
    ro = /*error:INVALID_ASSIGNMENT*/o;
    ro = /*error:INVALID_ASSIGNMENT*/n;
-   ro = /*warning:DOWN_CAST_COMPOSITE*/rr;
+   ro = /*info:DOWN_CAST_COMPOSITE*/rr;
    ro = ro;
    ro = /*error:INVALID_ASSIGNMENT*/rn;
    ro = oo;
    ro = /*error:INVALID_ASSIGNMENT*/nn;
    ro = /*error:INVALID_ASSIGNMENT*/nnn;
 
-   rn = /*warning:DOWN_CAST_COMPOSITE*/r;
+   rn = /*info:DOWN_CAST_COMPOSITE*/r;
    rn = /*error:INVALID_ASSIGNMENT*/o;
    rn = /*error:INVALID_ASSIGNMENT*/n;
    rn = /*error:INVALID_ASSIGNMENT*/rr;
    rn = /*error:INVALID_ASSIGNMENT*/ro;
    rn = rn;
    rn = /*error:INVALID_ASSIGNMENT*/oo;
    rn = /*error:INVALID_ASSIGNMENT*/nn;
    rn = /*error:INVALID_ASSIGNMENT*/nnn;
 
-   oo = /*warning:DOWN_CAST_COMPOSITE*/r;
-   oo = /*warning:DOWN_CAST_COMPOSITE*/o;
+   oo = /*info:DOWN_CAST_COMPOSITE*/r;
+   oo = /*info:DOWN_CAST_COMPOSITE*/o;
    oo = /*error:INVALID_ASSIGNMENT*/n;
-   oo = /*warning:DOWN_CAST_COMPOSITE*/rr;
-   oo = /*warning:DOWN_CAST_COMPOSITE*/ro;
+   oo = /*info:DOWN_CAST_COMPOSITE*/rr;
+   oo = /*info:DOWN_CAST_COMPOSITE*/ro;
    oo = /*error:INVALID_ASSIGNMENT*/rn;
    oo = oo;
    oo = /*error:INVALID_ASSIGNMENT*/nn;
    oo = /*error:INVALID_ASSIGNMENT*/nnn;
 
    nn = /*error:INVALID_ASSIGNMENT*/r;
    nn = /*error:INVALID_ASSIGNMENT*/o;
-   nn = /*warning:DOWN_CAST_COMPOSITE*/n;
+   nn = /*info:DOWN_CAST_COMPOSITE*/n;
    nn = /*error:INVALID_ASSIGNMENT*/rr;
    nn = /*error:INVALID_ASSIGNMENT*/ro;
    nn = /*error:INVALID_ASSIGNMENT*/rn;
    nn = /*error:INVALID_ASSIGNMENT*/oo;
    nn = nn;
    nn = nnn;
 
    nnn = /*error:INVALID_ASSIGNMENT*/r;
    nnn = /*error:INVALID_ASSIGNMENT*/o;
-   nnn = /*warning:DOWN_CAST_COMPOSITE*/n;
+   nnn = /*info:DOWN_CAST_COMPOSITE*/n;
    nnn = /*error:INVALID_ASSIGNMENT*/rr;
    nnn = /*error:INVALID_ASSIGNMENT*/ro;
    nnn = /*error:INVALID_ASSIGNMENT*/rn;
    nnn = /*error:INVALID_ASSIGNMENT*/oo;
-   nnn = /*warning:DOWN_CAST_COMPOSITE*/nn;
+   nnn = /*info:DOWN_CAST_COMPOSITE*/nn;
    nnn = nnn;
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_objectsWithCallMethods() async {
     await checkFile('''
 typedef int I2I(int x);
 typedef num N2N(num x);
 class A {
    int call(int x) => x;
 }
 class B {
    num call(num x) => x;
 }
 int i2i(int x) => x;
 num n2n(num x) => x;
 void main() {
    {
      I2I f;
      f = new A();
      f = /*error:INVALID_ASSIGNMENT*/new B();
      f = i2i;
      f = /*error:INVALID_ASSIGNMENT*/n2n;
-     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/i2i as Object;
-     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/n2n as Function;
+     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_COMPOSITE*/i2i as Object;
+     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_COMPOSITE*/n2n as Function;
    }
    {
      N2N f;
      f = /*error:INVALID_ASSIGNMENT*/new A();
      f = new B();
      f = /*error:INVALID_ASSIGNMENT*/i2i;
      f = n2n;
-     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/i2i as Object;
-     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/n2n as Function;
+     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_COMPOSITE*/i2i as Object;
+     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_COMPOSITE*/n2n as Function;
    }
    {
      A f;
      f = new A();
      f = /*error:INVALID_ASSIGNMENT*/new B();
      f = /*error:INVALID_ASSIGNMENT*/i2i;
      f = /*error:INVALID_ASSIGNMENT*/n2n;
      f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/i2i as Object;
      f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/n2n as Function;
    }
@@ skipping 84 matching lines @@
   {
     Iterable/*<R>*/ f/*<P, R>*/(List/*<P>*/ p) => null;
     List/*<T>*/ g/*<S, T>*/(Iterable/*<S>*/ s) => null;
 
     var local = f;
     local = g; // valid
 
     var local2 = g;
     local = local2;
     local2 = /*error:INVALID_CAST_FUNCTION*/f;
-    local2 = /*warning:DOWN_CAST_COMPOSITE*/local;
+    local2 = /*info:DOWN_CAST_COMPOSITE*/local;
 
     // Non-generic function cannot subtype a generic one.
     local = /*error:INVALID_ASSIGNMENT*/(x) => null;
     local = /*error:INVALID_ASSIGNMENT*/nonGenericFn;
   }
 }
 ''');
   }
 
   test_functionTypingAndSubtyping_uninferredClosure() async {
@@ skipping 832 matching lines @@
   }
   // TODO(leafp): This case isn't handled yet.  This test checks
   // the case where two related classes are instantiated with related
   // but different types.
   Iterable<num> test2(bool b) {
     List<int> li;
     Iterable<double> id;
     int x =
         /*info:ASSIGNMENT_CAST should be error:INVALID_ASSIGNMENT*/
         b ? li : id;
-    return /*warning:DOWN_CAST_COMPOSITE should be pass*/b ? li : id;
+    return /*info:DOWN_CAST_COMPOSITE should be pass*/b ? li : id;
   }
 }
 ''');
   }
 
   test_leastUpperBounds_fuzzyArrows() async {
     await checkFile(r'''
 typedef String TakesA<T>(T item);
 
 void main() {
   TakesA<int> f;
   TakesA<dynamic> g;
   TakesA<String> h;
   g = h;
-  f = /*warning:DOWN_CAST_COMPOSITE*/f ?? g;
+  f = /*info:DOWN_CAST_COMPOSITE*/f ?? g;
 }
 ''');
   }
 
   test_loadLibrary() async {
     addFile('''library lib1;''', name: '/lib1.dart');
     await checkFile(r'''
 import 'lib1.dart' deferred as lib1;
 import 'dart:async' show Future;
 main() {
@@ skipping 528 matching lines @@
     lOfOs = mOfAs;
     lOfOs = lOfDs;
     lOfOs = lOfOs;
     lOfOs = lOfAs;
     lOfOs = new L<Object>(); // Reset type propagation.
   }
   {
     lOfAs = /*error:INVALID_ASSIGNMENT*/mOfDs;
     lOfAs = /*error:INVALID_ASSIGNMENT*/mOfOs;
     lOfAs = mOfAs;
-    lOfAs = /*warning:DOWN_CAST_COMPOSITE*/lOfDs;
+    lOfAs = /*info:DOWN_CAST_COMPOSITE*/lOfDs;
     lOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
     lOfAs = lOfAs;
     lOfAs = new L<A>(); // Reset type propagation.
   }
   {
     mOfDs = mOfDs;
     mOfDs = mOfOs;
     mOfDs = mOfAs;
     mOfDs = /*info:DOWN_CAST_IMPLICIT*/lOfDs;
     mOfDs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
     mOfDs = /*error:INVALID_ASSIGNMENT*/lOfAs;
     mOfDs = new M(); // Reset type propagation.
   }
   {
     mOfOs = mOfDs;
     mOfOs = mOfOs;
     mOfOs = mOfAs;
     mOfOs = /*info:DOWN_CAST_IMPLICIT*/lOfDs;
     mOfOs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
     mOfOs = /*error:INVALID_ASSIGNMENT*/lOfAs;
     mOfOs = new M<Object>(); // Reset type propagation.
   }
   {
-    mOfAs = /*warning:DOWN_CAST_COMPOSITE*/mOfDs;
+    mOfAs = /*info:DOWN_CAST_COMPOSITE*/mOfDs;
     mOfAs = /*info:DOWN_CAST_IMPLICIT*/mOfOs;
     mOfAs = mOfAs;
-    mOfAs = /*warning:DOWN_CAST_COMPOSITE*/lOfDs;
+    mOfAs = /*info:DOWN_CAST_COMPOSITE*/lOfDs;
     mOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
     mOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfAs;
   }
 }
 ''');
   }
 
   test_setterOverride_fuzzyArrows() async {
     await checkFile('''
 typedef void ToVoid<T>(T x);
@@ skipping 282 matching lines @@
   // type is effectively:              (Object, Object) -> int
   // We are assigning it a fn of type: (Comparable, Comparable) -> int
   // There's no telling if that will work. For example, consider:
   //
   //     new SplayTreeMap<Uri>();
   //
   // This would end up calling .compareTo() on a Uri, which doesn't
   // define that since it doesn't implement Comparable.
   SplayTreeMap([int compare(K key1, K key2),
                 bool isValidKey(potentialKey)])
-    : _comparator = /*warning:DOWN_CAST_COMPOSITE*/(compare == null) ? Comparable.compare : compare,
+    : _comparator = /*info:DOWN_CAST_COMPOSITE*/(compare == null) ? Comparable.compare : compare,
       _validKey = (isValidKey != null) ? isValidKey : ((v) => true) {
 
     // NOTE: this is a down cast because isValidKey has fuzzy arrow type.
-    _Predicate<Object> v = /*warning:DOWN_CAST_COMPOSITE*/(isValidKey != null)
+    _Predicate<Object> v = /*info:DOWN_CAST_COMPOSITE*/(isValidKey != null)
         ? isValidKey : (/*info:INFERRED_TYPE_CLOSURE*/(_) => true);
 
     v = (isValidKey != null)
          ? v : (/*info:INFERRED_TYPE_CLOSURE*/(_) => true);
   }
 }
 void main() {
   Object obj = 42;
   dynamic dyn = 42;
   int i = 42;
@@ skipping 104 matching lines @@
     // Regression test for:
     // https://github.com/dart-lang/sdk/issues/27040
     await checkFile(r'''
 void f/*<T extends num>*/(T x, T y) {
   var z = x;
   var f = () => x;
   f = () => y;
   if (x is int) {
     /*info:DYNAMIC_INVOKE*/z./*error:UNDEFINED_GETTER*/isEven;
     var q = x;
-    q = /*warning:DOWN_CAST_COMPOSITE*/z;
+    q = /*info:DOWN_CAST_COMPOSITE*/z;
     /*info:DYNAMIC_INVOKE*/f()./*error:UNDEFINED_GETTER*/isEven;
 
     // This does not capture the type `T extends int`. Instead the return type
     // is `T extends num`. What happens is we substitute {T/T} on the function
     // type, and the way it is implemented, this leads back to `T extends num`.
     // See https://github.com/dart-lang/sdk/issues/27725
     var g = () => x;
     g = f;
     /*info:DYNAMIC_INVOKE*/g()./*error:UNDEFINED_GETTER*/isEven;
-    q = /*warning:DOWN_CAST_COMPOSITE*/g();
+    q = /*info:DOWN_CAST_COMPOSITE*/g();
     int r = x;
   }
 }
     ''');
   }
 
   test_typeSubtyping_assigningClass() async {
     await checkFile('''
 class A {}
 class B extends A {}
@@ skipping 256 matching lines @@
 class CheckerTest_Driver extends CheckerTest {
   @override
   bool get enableNewAnalysisDriver => true;
 
   @failingTest
   @override
   test_covariantOverride_fields() async {
     await super.test_covariantOverride_fields();
   }
 }